Trouble with XPS 15 9550, USB-C/Thunderbolt 3, and external monitors

After the time spent with Dell Support doing diagnostics and updating video drivers to those official Dell drivers on the support page, my new XPS 15 9550 with 4K touch display continues to struggle when using external monitors. I have two (2) Dell U2515H monitors.

I have updated ALL of the drivers and BIOS to the very latest files available on the Dell support page, including the newest Thunderbolt 3 driver.

When the laptop is NOT connected to any external monitors, I am NOT experiencing any trouble.

When the laptop is connected to ONE external monitor via the onboard HDMI port, I am NOT experiencing any trouble.

Trouble begins with the addition of ANY external monitor via the USB-C/Thunderbolt 3 port.

I have experimented with the following three adapters, all producing the same result:

Dell USB-C to HDMI (2.0), part number 047KD7

Dell USB-C Port DA200, part number 5KMR3 REVA00

Cable Matters USB-C to DisplayPort

First, regardless of which adapter. my laptop ramps up the fan for as long as the adapter is present.

Second, although the monitor works with any of the adapters at the proper resolution, all of the screens will go black about every 10-20 minutes and the displays will seem to resize and reset. In this process, about half of the time, the windows open on the monitor connected to the USB-C/Thunderbolt 3 port will either minimize or relocate to the primary display (the laptop screen). However, the laptop itself doesn't freeze. I tried running a YouTube video through the screen freeze event. The sound continued without any trouble and the video advanced through the timeline and was synchronized to the sound when the displays reset.

If I disconnect the USB-C adapter (whichever one), the laptop fan will return to an idle state and the display freezes also stop.

I think that the USB-C/Thunderbolt 3 driver and/or the external display driver is/are to blame and I strongly urge that Dell get this resolved ASAP.

This experience is VERY frustrating, especially considering the premium cost of the XPS 15. I intentionally purchased a top-of-line laptop and fully expect it to be able to at least drive a second monitor with the super magical Thunderbolt 3 port. I am seriously considering returning the device and looking elsewhere.

This is apparently a problem with the Thunderbolt 3 driver/firmware and/or the Intel 530 graphics drivers. I see very similar issues using Dells new TB15 Thunderbolt 3 Dock. Normally when I'm in my home office I use my 9550 with the lid closed using an external monitor connected to the HDMI port. All works perfectly. When I try to use the Dell Thunderbolt 3 Dock and connect my external display to its HDMI port it is unstable. Sometimes the external screen goes blank for a few seconds. When the system wakes up from sleep or I reboot it it does not come up on the external display but I have to open the laptop and switch back to the external monitor. Basically it is unusable. Still waiting for Dell to fix the issues.

I have the same problem with a DisplayPort connection using the XPS 15 9550 and an external display. Are you running Windows 10? I've speculated that the half completed Control Panel ==> Settings overhaul isn't fully blocking the "closing the lid" power-management functionality, even with the "Do Nothing" setting in vogue. The laptop may be erroneously and ineffectually sending the signal to the display to sleep. But if the same problem exists in Windows 8.x, then that theory seems unlikely. It's a pity Dell doesn't offer the option in BIOS to select what the laptop does when the lid is closed.

I have the TB15 Dell Thunderbolt Dock too. Whether I connect the DisplayPort cable to a Thunderbolt 3 adapter or the Dell Thunderbolt Dock the results are the same. I don't think the Dock plays a role. You say the blinking off and on problem doesn't happen with HDMI, that would indicate that the Thunderbolt 3/USB-C port, or more likely its controller software (which Dell updated only a few days ago), is at fault. I suspect Dell will get this ironed out in time. They are really good about updating their drivers, firmware etc. But they need to know about the problem.

I contacted support and had a very long dialogue with them that lasted over a month. But because my machine is 4K and my external monitor is 4K, I never thought to use the onboard laptop's HDMI 1.4 port, which does not support 4K at 60Hz. But I'm going to try it tomorrow. By the way, it's definitely not your monitor. I've experienced the same problem with three different Dell 4K monitors now.

I'd appreciate it if you came back and posted what version of Windows you're using.

I'm running Windows 10 pro. As I said, normally I run with the laptop lid closed and my external monitor connected using the laptop HDMI port and everything works perfectly. It's only when I try to use the TB15 Thunderbolt 3 dock and connect my monitor to the HDMI port on the dock that I experience the problems. My monitor also has a VGA port so I did try the VGA port on the dock rather than the HDMI port and experienced the same problems. Based on what I am seeing, and others, like you, reporting similar problems, it seems pretty clear it's a driver issue. Hopefully Dell will get it fixed sooner rather than later.

I updated the Intel video driver to the latest direct from Intel by deleting the Dell driver. Didn't help. For now, I've rolled back to the latest Dell issued Intel video driver.

I rolled back on the nVidia driver to the latest Dell issued version. Didn't help. I've since let that driver automatically update to the latest direct from nVidia.

I was hopeful when I saw the new Thunderbolt 3 driver. Didn't help.

I noticed that the max resolution on the Dell DA200 "mini-dock" HDMI port is somewhere below that of the dedicated USB-C to HDMI cable. The DA200 didn't reach to the native resolution of my monitors, which is 2560x1440. Disappointed in that, as I liked the idea of it and gig ethernet port running simultaneously. One fact on this front is that when I had the DA200 connected via HDMI to my 3rd screen AND the ethernet port in use, the ethernet port also went flaky when the display events occurred. Really, really strong evidence of a Thunderbolt 3 problem, right? I'd be curious to know if those using the new Thunderbolt docking station have noticed the other ports going flaky during the display events.

I've temporarily given up on the Thunderbolt 3 port. I ordered a Plugable USB 3.0 to 4K HDMI that does 2560x1440 at 60 hz (DisplayLink drivers). I've always had great success with my Plugable video cards and, while waiting for UPS, I'm presently using an older Plugable USB 3.0 to DVI unit connected to an older monitor as display #3. No problems whatsoever and no crazy fan speeds. In fact, except for which ports are being used, I'm set up and stable the way I hoped.

I have some confidence that Dell will get this fixed. In fact, I kind of blame Intel - it's their chipset and tech. Perhaps that is what I deserve for being ahead of all the accessory set for the USB-C/Thunderbolt 3 port. I see that even noted Googler, Benson Leung, who had taken it upon himself to 3rd party validate USB-C cables, was burned (literally) when a shoddy cable fried his beautiful Chromebook Pixel and several pieces of kit connected to it.

So, I'll fix my immediate problem and wait for Dell to fix theirs. I have plenty of adapters to choose from when that magical Thunderbolt 3 port decides to work (without turning my fan into a drone motor).

Good afternoon. I have same issue. I believe I fixed by checking the "do nothing when lid closed" not only for when plugged in but also when on battery. I believe has to do with the charger in the dock not providing enough power. Seems silly given that my XPS 15 and the TB15 Dock are marketed together. Hope there is a fix soon as i really do not like that setting.

Hi. Some conflicting information: Like you, I have my "set what happens when lid closes" setting on "do nothing" for both battery and AC power, but I still have the problem that with the lid closed, the monitor blinks off for about five seconds and then back on, repeating that miscue every 3 to 4 minutes. My experience has also been that the issue has nothing to do with the TB15 dock. I can also use a DisplayPort connection that starts with an adapter plugged in to the USB-C/Thunderbolt 3 port. I have the same problems in that configuration as I do connected to the Dell Thunderbolt Dock.

So, that said, if you have solved the problem, can you think some more about how you did it? I'm sure that all of us and many more besides would really appreciate your information!

The problem is actually worse then just the fan running.. try plugging in a usb keyboard, wireless or not and a wireless USB mouse.. The mouse skips around and the keyboard either misses characters or it repeats characters randomly. the system acts as if it is being overtaxed and is unable to perform well.. everything goes much slower and struggles. And yes I have all drivers and bio updates.. Dell claims I'm not using compatible port replicators.. but i bought the one linked to the 9550 page.. Then they tell me this is not compatible since it shows only latitude compatibility. The version of DA200 that is compatible is only available in singapore?? strange, all of this.

DELL - are you listening to all the comments about this issue?? You have a major issue on your hands. If I didn't like everything else about the laptop I'd return it in a heartbeat.